1. Field of the Invention
The present invention relates to a communication system, and, more particularly, to a communication system which controls communication of information about whether or not a third party is present over a network.
2. Description of the Related Art
Today communication networks are demanded of multifarious functions and the network structures are becoming complex and enormously larger. There are growing demands that a caller wants, beforehand, presence information indicating whether or not a communicating party is on such a communication network.
Prior art that is associated with control on presence information is disclosed in, for example, Japanese Unexamined Patent Publication (KOKAI) No. 207938/1998. This prior art places a server on a network to manage presence information.
The prior art controls presence information of only those terminals that are registered in the server which executes centralized management of presence information, and does not provide flexible control on presence information among terminals which are not registered in the server. That is, the prior art suffers poor flexibility and serviceability.
In addition, the conventional control of presence information reflects no considerations on exchange services, such as a multiline reception capability and pickup response capability.